ZENER DIODE

  • In  a  general  purpose  PN  diode  the  doping  is  light;  as  a  result  of  this  thebreakdown  voltage  is  high.  If  a  P  and  N  region  are  heavily  doped  then  the breakdown voltage can be reduced.
  • When the doping is heavy even the reverse voltage is low, the electric field atbarrier  will  be  so  strong  thus  the  electrons  in the  covalent  bands  can  break away from the bonds. This effect is known as zener effect.
  • A  diode  which  exhibits  the  zener  effect  is  called  a  zener  diode.  Hence  it  isdefined as a reverse biased heavily doped PN junction diode which operates in breakdown   region.   The   zener   diodes   have   been   designed   to   operate   at voltages ranging from a few volts to several hundred volts.
  • Zener breakdown occurs in junctions which is heavily doped and have narrowdepletion layers. The  breakdown voltage sets up a  very strong  electric field.    This  field  is  strong  enough  to  break  or  rupture  the  covalent  bonds  thereby generating electron hole pairs.
  • Even a small reverse voltage is capable of producing large number of currentcarrier, When a zener diode is operated in the breakdown region care must be taken to see that the power dissipation across the junction is within the power rating  of  the  diode  otherwise  heavy  current  flowing  through  the  diode  may destroy it.
Equivalent Circuit of Zener diode

The schematic symbol and its equivalent circuit are shown in figure 14. It is similar to that of normal diode except the line representing cathode is bent both ends are shown in figure 14.



V-I Characteristics of zenerdiode


The forward characteristic of a zener diode is similar to that of a P N Junction diode. The reverse characteristic of zener diode is obtained as follows.

  • The reverse current that is present at the origin and the knee of the curve isdue to the reverse leakage current due to the minority carriers. This current is specified by stating its value at 80% of the zener voltage Vz
  • As  the  reverse  voltage  is  gradually  increased,  the  breakdown  occurs  at  theknee  and  the  current  increases  rapidly.  To  control  this  current  a  suitable external  resistance  has  to  be  used.  The  maximum  permissible  value  of  the current is denoted by Izmax. The minimum usable current is Izmin
  • The  voltage  across  the  terminals  of  the  diode  for  a  current  Iz  which  is  theapproximate  midpoint  of  the  linear  range  of  the  reverse  characteristics  in called the zener voltage Vz. At the knee point, the breakdown voltage remains constant  between  Izmax  and  Izmin.  This  ability  of  a  diode  is  called  regulating ability and is an important feature of a zenerdiode.

Application of Zener Diode

It can be used


a) As voltage regulators

b) As peak clippers

c) For reshaping waveforms

d) For meter protection against damage from accidental application of excessive voltage

3 comments:

  1. Examine the most piece of standard neglecting winding machine is used for twist bowing transformer with excellent apparatus. The standard transformer winding machine is a lone line of plastic models and faker piece. The transformer is on basic parts of the electrical unit, recalling a definitive concentration to the winding machines are having enormous structure.Magnet Wire

    ReplyDelete
  2. At the present time in stabilizer, the inductance wind creation and some novel occasions can see the use of this model.

    The Winding Machines are amalgamate with the most recent CNC control with alpha-numeric screen that has two or four lines uninhibitedly, which demonstrate essential information for the working staff. For instance, the norms are utilizing like as number of working advances, number of turns, feeling of sensation, and undertaking of things.Inductor Winding

    ReplyDelete
  3. The standard transformer winding machine is a lone line of plastic models and fraud fragment. The transformer is on immense parts of the electrical unit, recollecting a definitive goal to the winding machines are having tremendous structure.Inductor Winding

    ReplyDelete

Labels

PROJECTS 8086 PIN CONFIGURATION 80X86 PROCESSORS TRANSDUCERS 8086 – ARCHITECTURE Hall-Effect Transducers INTEL 8085 OPTICAL MATERIALS BIPOLAR TRANSISTORS INTEL 8255 Optoelectronic Devices Thermistors thevenin's theorem MAXIMUM MODE CONFIGURATION OF 8086 SYSTEM ASSEMBLY LANGUAGE PROGRAMME OF 80X86 PROCESSORS POWER PLANT ENGINEERING PRIME MOVERS 8279 with 8085 MINIMUM MODE CONFIGURATION OF 8086 SYSTEM MISCELLANEOUS DEVICES MODERN ENGINEERING MATERIALS 8085 Processor- Q and A-1 BASIC CONCEPTS OF FLUID MECHANICS OSCILLATORS 8085 Processor- Q and A-2 Features of 8086 PUMPS AND TURBINES 8031/8051 MICROCONTROLLER Chemfet Transducers DIODES FIRST LAW OF THERMODYNAMICS METHOD OF STATEMENTS 8279 with 8086 HIGH VOLTAGE ENGINEERING OVERVOLATGES AND INSULATION COORDINATION Thermocouples 8251A to 8086 ARCHITECTURE OF 8031/8051 Angle-Beam Transducers DATA TRANSFER INSTRUCTIONS IN 8051/8031 INSTRUCTION SET FOR 8051/8031 INTEL 8279 KEYBOARD AND DISPLAY INTERFACES USING 8279 LOGICAL INSTRUCTIONS FOR 8051/8031 Photonic Transducers TECHNOLOGICAL TIPS THREE POINT STARTER 8257 with 8085 ARITHMETIC INSTRUCTIONS IN 8051/8031 LIGHTNING PHENOMENA Photoelectric Detectors Physical Strain Gage Transducers 8259 PROCESSOR APPLICATIONS OF HALL EFFECT BRANCHING INSTRUCTIONS FOR 8051/8031 CPU OF 8031/8051 Capacitive Transducers DECODER Electromagnetic Transducer Hall voltage INTEL 8051 MICROCONTROLLER INTEL 8251A Insulation Resistance Test PINS AND SIGNALS OF 8031/8051 Physical Transducers Resistive Transducer STARTERS Thermocouple Vacuum Gages USART-INTEL 8251A APPLICATIONs OF 8085 MICROPROCESSOR CAPACITANCE Data Transfer Instructions In 8086 Processors EARTH FAULT RELAY ELECTRIC MOTORS ELECTRICAL AND ELECTRONIC INSTRUMENTS ELECTRICAL BREAKDOWN IN GASES FIELD EFFECT TRANSISTOR (FET) INTEL 8257 IONIZATION AND DECAY PROCESSES Inductive Transducers Microprocessor and Microcontroller OVER CURRENT RELAY OVER CURRENT RELAY TESTING METHODS PhotoConductive Detectors PhotoVoltaic Detectors Registers Of 8051/8031 Microcontroller Testing Methods ADC INTERFACE AMPLIFIERS APPLICATIONS OF 8259 EARTH ELECTRODE RESISTANCE MEASUREMENT TESTING METHODS EARTH FAULT RELAY TESTING METHODS Electricity Ferrodynamic Wattmeter Fiber-Optic Transducers IC TESTER IC TESTER part-2 INTERRUPTS Intravascular imaging transducer LIGHTNING ARRESTERS MEASUREMENT SYSTEM Mechanical imaging transducers Mesh Current-2 Millman's Theorem NEGATIVE FEEDBACK Norton's Polarity Test Potentiometric transducers Ratio Test SERIAL DATA COMMUNICATION SFR OF 8051/8031 SOLIDS AND LIQUIDS Speed Control System 8085 Stepper Motor Control System Winding Resistance Test 20 MVA 6-digits 6-digits 7-segment LEDs 7-segment A-to-D A/D ADC ADVANTAGES OF CORONA ALTERNATOR BY POTIER & ASA METHOD ANALOG TO DIGITAL CONVERTER AUXILIARY TRANSFORMER AUXILIARY TRANSFORMER TESTING AUXILIARY TRANSFORMER TESTING METHODS Analog Devices A–D BERNOULLI’S PRINCIPLE BUS BAR BUS BAR TESTING Basic measuring circuits Bernoulli's Equation Bit Manipulation Instruction Buchholz relay test CORONA POWER LOSS CURRENT TRANSFORMER CURRENT TRANSFORMER TESTING Contact resistance test Current to voltage converter DAC INTERFACE DESCRIBE MULTIPLY-EXCITED Digital Storage Oscilloscope Display Driver Circuit E PROMER ELPLUS NT-111 EPROM AND STATIC RAM EXCITED MAGNETIC FIELD Electrical Machines II- Exp NO.1 Energy Meters FACTORS AFFECTING CORONA FLIP FLOPS Fluid Dynamics and Bernoulli's Equation Fluorescence Chemical Transducers Foil Strain Gages HALL EFFECT HIGH VOLTAGE ENGG HV test HYSTERESIS MOTOR Hall co-efficient Hall voltage and Hall Co-efficient High Voltage Insulator Coating Hot-wire anemometer How to Read a Capacitor? IC TESTER part-1 INSTRUMENT TRANSFORMERS Importance of Hall Effect Insulation resistance check Insulator Coating Knee point Test LEDs LEDs Display Driver LEDs Display Driver Circuit LM35 LOGIC CONTROLLER LPT LPT PORT LPT PORT EXPANDER LPT PORT LPT PORT EXTENDER Life Gone? MAGNETIC FIELD MAGNETIC FIELD SYSTEMS METHOD OF STATEMENT FOR TRANSFORMER STABILITY TEST METHODS OF REDUCING CORONA EFFECT MULTIPLY-EXCITED MULTIPLY-EXCITED MAGNETIC FIELD SYSTEMS Mesh Current Mesh Current-1 Moving Iron Instruments Multiplexing Network Theorems Node Voltage Method On-No Load And On Load Condition PLC PORT EXTENDER POTIER & ASA METHOD POWER TRANSFORMER POWER TRANSFORMER TESTING POWER TRANSFORMER TESTING METHODS PROGRAMMABLE LOGIC PROGRAMMABLE LOGIC CONTROLLER Parallel Port EXPANDER Paschen's law Piezoelectric Wave-Propagation Transducers Potential Transformer RADIO INTERFERENCE RECTIFIERS REGULATION OF ALTERNATOR REGULATION OF THREE PHASE ALTERNATOR Read a Capacitor SINGLY-EXCITED SOLIDS AND LIQUIDS Classical gas laws Secondary effects Semiconductor strain gages Speaker Driver Strain Gages Streamer theory Superposition Superposition theorem Swinburne’s Test TMOD TRANSFORMER TESTING METHODS Tape Recorder Three-Phase Wattmeter Transformer Tap Changer Transformer Testing Vector group test Virus Activity Voltage Insulator Coating Voltage To Frequency Converter Voltage to current converter What is analog-to-digital conversion Windows work for Nokia capacitor labels excitation current test magnetic balance voltage to frequency converter wiki electronic frequency converter testing voltage with a multimeter 50 hz voltages voltmeter

Search More Posts

Followers